The invention relates to a filtrate separating device, especially for sewage sludge disposal, with a receiving space for sludge to be filtered, a frame connecting a pair of walls defining the receiving space, at least one filter mat, placed on a wall in the receiving space for solid/liquid separation, a sludge intake connected to the receiving space and a filtrate drain connected to the space between each wall and filter mat; wherein, for the removal of the dry filter cake, freed from filtrate, the walls are moved away from one another and the frame is opened.
Filtrate separating devices of the type under discussion are an indispensable means, especially in the field of sewage sludge disposal, for disposing of sewage sludge economically. In such a filtrate separating device, the liquid filtrate is pressed out of the sewage sludge so that, finally, to the greatest extent possible, only a dry filter cake remains which can either be disposed of or processed further, especially burned. Problems similar to those occurring in sewage sludge disposal also occur in other fields. For example, such problems arise in the field of paint sludge disposal from paint shops, in the food industry, and for garbage compaction with or without liquid accumulation.
The known filtrate separating devices consist of a plurality of plates placed vertically and lined up successively, whose front and back surfaces form the walls of receiving spaces, formed between the plates, for the sludge to be filtered. An central intake opening running through the plates forms the sludge intake to the receiving spaces. The receiving spaces between the individual plates are sealed relative to the outside by a frame. The walls have a plurality of duct-like moldings, which are brought together in a filtrate drain placed at the lower end of each wall. Each wall provided with ducts is covered with a flexible filter mat, which is fastened to the frame. All of the plates are connected to one another by standards running in the longitudinal direction. With the usual size of the plates being about 2 to 4 square meters, such a device with a total of 40 plates weighs about 25 tons.
In operation, the plates are moved together by a hydraulic press and occupy a firmly preset space, by which the receiving spaces between the plates are defined. Then, the sewage sludge (or another medium to be filtered) is introduced into the receiving spaces by the sludge intake under high pressure. The sewage sludge is pressed out by the filling pressure of the sewage sludge. The filtrate from each receiving space can drain into the filtrate drain by the duct structure of the surfaces of the plates. If it turns out that the receiving spaces become clogged, the filtering process is ended. The plates are moved away from one another and the now largely dry filter cakes are removed from the various receiving spaces.
The description given above of the prior art makes it clear that filtrate separating devices of the usual design can be used only in large frames and require a complex design and costly expenditure. The problem of the known filtrate separating device is, thus, that it is too complicated, too bulky and requires too much plant engineering as well as being too expensive.